Our present invention relates to an apparatus for applying at least one facing foil to a face of a board and, more particularly, to a foil-application apparatus for upper-side and/or lower-side applications of facing foils to carrier boards.
The term xe2x80x9cboardxe2x80x9d or xe2x80x9ccarrier boardxe2x80x9d as used herein is intended to refer, generally, to a structural board which can be composed of particles (particle board) such as fibers (fiber board) or chips (chip board) usually of cellulosic material, e.g. wood. The expressions also apply to laminated boards which can have particle layers or nonparticle layers laminated together by glue or adhesive and to boards laminated from layers of other materials. Such boards are widely used in interior decoration, as paneling for lining rooms and the like and for other decorative or structural purposes.
The foils referred to herein can be foils of decorative paper with various designs, illustrations and printed or photographically-reproduced patterns, other papers which themselves can be laminated from one or more sheets or foils, synthetic resin foils which can be embossed or plain, opaque or transparent, patterned or nonpatterned and the foils may include veneering foils as well.
Such foils are intended to face the board and cover an unaesthetic carrier body with faces of aesthetic value. The foils applied to the board can be bonded thereto in continuous processes or in single-stage or multistage processes.
An apparatus for applying foils to such boards in the art has required two foil pallets or foil stacks. When the board is to be covered on its upper side as well as on its underside with such foils, a respective foil is drawn from each stack. This is especially the case when the foils are decorative papers in which the decor appears only on one side of the paper. At the upper face of the board, the decor must be upwardly while on the underside of the board the decor must face downwardly and the foils in the two stacks are thus oriented accordingly. In the past it has been practically impossible with a simple and economical apparatus to apply a foil from one stack with its decor facing upwardly to the upper surface of the board and the same foil facing downwardly to the lower surface of the foil. As a consequence, the foils were applied to the board by an upper stage and a lower stage with the stacks disposed respectively at the upper level and the lower level and the foils of the stacks oriented appropriately.
In the handling of paper sheets (DE 25 49 903) in the printing field, it is known to engage a sheet from a stack and swing the engaging unit through 180xc2x0 above a horizontal axis to invert that sheet. To date these systems have not found successful application in the laminating field, in the board-making field and in the application of facing foils to board faces.
It is, therefore, the principal object of the present invention to provide a foil-application apparatus for the purposes described which can apply foils with the proper orientations to both the upper side of a board and to the lower side of a board economically and reliably, without drawbacks of earlier sheet-inverting systems and without having to turn over a foil stack for that purpose.
Another object of the invention is to provide an improved apparatus for applying at least one facing foil selectively to the upper or lower face of a board which can use a single stack of the foil from which the foils can be drawn for application to the upper and lower sides, respectively.
A further object of this invention is to provide a foil-applying apparatus for boards of the type described whereby disadvantages of earlier systems are obviated.
These objects and others which will become apparent hereinafter are attained, in accordance with the invention in an apparatus for applying at least one facing foil to a face of a board which comprises:
a board conveyor for displacing a board to be faced along a board-transport path in a direction of advance;
first holding means above the path for supporting a stack of foils applicable to a surface of a board displaceable along the path;
a first suction device capable of entraining foils from the stack and movable back and forth above the stack;
a first foil deliverer downstream of the stack in the direction and receiving foils from the first suction device;
a first foil feeder between the first foil deliverer and the path for depositing a foil received from the first foil deliverer onto a board on the conveyor;
a second foil deliverer upstream of the stack relative to the direction;
a second suction device capable of entraining foils from the stack and movable back and forth above the stack and depositing foils upon the second foil deliverer; and
a foil-turning device upstream of the stack relative to the direction, the foil-turning device comprising a suction path guiding foils through 180xc2x0 from an inlet adjacent the second foil deliverer to an outlet proximal to the conveyor and receiving foils deposited upon the second foil deliverer by the second suction device and inverting foils passing along the suction path for application to a board on the conveyor.
According to the invention, above the board-transport path, a board lifter is provided for raising a board from the board-transport path whereby the foil-turning device can feed a foil beneath the board and the board can be lowered onto the foil beneath the board.
The board lifter can be a suction device and at least one of those deliverers is formed by a telescopic transfer platform and a foil path of foils from the stack along the first foil-deliverer and the first foil-feeder, adjustable for different path lengths.
Each of the deliverers is provided with a blower device for supporting respective foils above respective platforms. Preferably the suction path is formed by a substantially semicircular suction-belt path.
In addition the apparatus can comprise a lower foil applicator with a second foil stack, a third suction device for entraining foils from the second stack, a third foil-feeder for applying a foil from the second stack to an underside of a board on the board-transport path, and a third foil-deliverer between the second stack and the second foil feeder.
It will be apparent that the heart of the invention is the provision, upstream of the first foil stack in the direction of advance of the plate of a foil-turning device forming a suction path for the foil guiding it over about 180xc2x0 from a mouth of that path adjoining the second foil deliverer onto which the second suction device entrains foils from the same stack that the first suction device delivers those foils ultimately to the top of the board.
That foil suction path ends beneath the level of the stack but above the board conveyor so that, with lifting of the board from the conveyor, an inverted foil can be fed from the first stack beneath the board and can coat the downwardly-turned face of the board with this inverted foil. The top of the board is covered with the first foil in the normal manner and the board now stacked with upper and lower foils can be subjected to lamination. The boards thus receive upper and lower facing foils from a single foil stack located at a single level or stage.
The apparatus of the invention is highly versatile since it allows, with proper adjustment of the outlet of the suction path of the foils, to be located above the board on the conveyor and thus for applying the inverted foil to the upper surface.
When the inverted foil is to be applied to the downwardly-turned face of the board, the board lifter, which can be provided with suction cups which are applied to the board at its upper surface, can lift the board to the extent necessary to allow the inverted foil to be fed beneath the boards. The lifting device can then be lowered to place the board on the inverted foil. The board is stopped for this operation and after the board is placed on the lower foil, the board is again advanced by the conveyor for application of the upper foil in its normal orientation, the upper and lower foils both deriving from the same stack.
The result is a simple reliable two-sided covering of the board with a minimum expenditure of time even when only a single stack of the foils may be available. The inversion does not require complex mechanisms.
According to a further feature of the invention at least the first foil deliverer is formed as a telescoping transfer platform and the transport path of at least the first suction device is adjustable to different path lengths. As a result, different foil sizes can be handled and each alignment of the foil with the board, where the foil meets the board, can always be ensured. The pick-up position and delivery position of the first suction device can likewise be adjusted accordingly. With changes in the foil size, the transfer platform and the foil feeder can be adjusted by reason of the telescoping configurations to assure proper alignment of the foil with the board.
Furthermore, the first foil-suction device and the second foil-suction device can be formed as suction bars which are separately displaceable or can be displaceable together on common guide rails parallel to the board conveyor and preferably at the same level or height above this conveyor.
The first and second foil deliverers or transfer platforms can themselves be equipped with blower devices on which the foil can be supported by air cushions which facilitate the transport of the foils over these platforms.
According to another feature of the invention, the foil inverter is formed by a substantially semicircular suction-belt path which transports the foils generally in a semicircle so that the underside of the transported foil is turned upwardly. The suction belts can serve to deliver the foil beneath the raised board. The board-raising device can also be formed with one or more lifting beams which have suction cups distributed over the surface of the board.
In a variant of the apparatus of the invention, beneath the board conveyor and the foil-inverting device, a separate lower foil applicator can be provided. This applicator can have a second foil stack, a third suction device movable back and forth, a third foil deliverer and a second foil feeder for applying the foil on the third deliverer to a board conveyor beneath a board thereon. In this case, the separate stacks are to provided on upper and lower levels and, while the decorative paper may be fed only from the first stack to both the upper and lower surfaces of the board, a transparent cover foil can be applied from the second stack below the board.
In addition, a third stack can be provided above the first stack and a separate suction device, a foil deliverer and foil feeder can be provided for the foils from the third stack. The latter foils also may be transparent or protective-cover foils if desired. Of course depending upon the foils in the stacks and the programming of the apparatus, a large variety of facing foils can be provided for a board.